Tesla Aims to Win Over Skeptics With Battery Swap Stations

Tesla Motors has added battery swap to its arsenal of technologies aimed at displacing gasoline-burning vehicles. Its chairman and CEO Elon Musk offered the demo.

Tesla Motors has added battery swap to its arsenal of technologies aimed at displacing gasoline-burning vehicles.

In a demonstration before a packed house of electric car enthusiasts, Tesla chairman and CEO Elon Musk showed how an automatic battery-switching system could remove a battery from a Tesla Model S and replace it in 90 seconds -- about two-and-a-half minutes less than it would take to refill a fuel tank at a gasoline station.

"What we really want to show here is that you can actually be more convenient than a gasoline car," Musk told a cheering audience at Tesla's design studio two weeks ago. "Hopefully, this is what convinces people that electric cars are the future."

Tesla's flat battery pack at the bottom of the Model S makes it possible for automated battery swap systems to replace the pack from underneath.(Source: Design News)

The upfront cost to the station owner seems to be somewhat more reasonable than the upfront cost of a hydrogen fuel station ($500k vs $1M). However, if a battery swap station requires a technician to be on board, the running cost will definitely higher than a gas station today.

The cost to consumer to swap a battery is $60 to $80. Let's assume a fully charge battery is able to move the car by 300 miles. This equates to $0.2 to $0.267 per mile. Given today's average gas price (in Bay Area) is around $4.00. This virtually means, by swapping battery, a tesla will achieve 20mpg for a $60 swap and 15mpg for a $80 swap. Now, owning a Model S for a long distance driving may look less impressive.

Battery swapping is an important technology to move electric car forward. The business and operational model have yet been figured out. Until then, fast charging station may still be the key component to drive EV forward. EV may stay as a commute car for a while.

Not a fair comparison. In the demo Musk did not take into consideration the time to arrange payment for the battery swap but he did for filling the car with gas.

Furthermore the economics just don't work. Battery swaps are to cost $60 but if you wait an extra 20 few minutes you get a free "fill-up". I would imagine most average people to which Musk hopes to sell to in a few years would pick the free fill-up every time unless it's an emergency and the economics simply would not be there to just service emergencies.

Distribution to the station also has to be accounted for. Battery distribution channels are much easier and cheaper to operatre than even gasoline distribution. However, pipelines and tanker trucks already exist for gasoline. There is next to nothing online for hydrogen and distribution would be very expensive.

I also very much doubt the 300 mile range claim. How was this range estimate calculated? On a flat test track at warm temperatures at a constant 30 mph?

Actually at a constant 30 mph Musk claims a range of over 425 miles for the Model S with an optimum range of over 450 miles at about 21 mph! A more realistic range under close to normal driving conditions would be close to 265 miles using EPA's 5-cycle test with aggressive driving lowering it even further. See Musk's blog post here, http://www.teslamotors.com/fr_FR/blog/model-s-efficiency-and-range

Yes, but he gives the conditions for the data in the chart. Constant speed, flat gound, no wind, climate control off, 300 lbs cargo including driver, windows closed, new battery pack. In other words, absolutely ideal conditions that in no way resemble real world use.

Yes, you're right. Those would be the necessary conditions to achieve the maximum range. However EPA's 5-cycle test includes "a cold driving cycle that requires heater use, a hot weather cycle with air conditioning operation, and a high-speed cycle (reaching 80mph) with rapid accelerations." This is certainly more realistic but it does cut the maximum range under ideal conditions by nearly half to 265 miles as I stated.